I am trying to make the following solid: a column which is square in x section at the top, then blends into round in x section lower down. The way i have been trying is by merging 2 solids: a tapering square section and a round section column. Then i would erase the various “corners” either side of the intersect line. However, no intersect line between these curved faces appears, and it is very difficult to go over by hand. How would you do it??

-The two shapes positioned to pass through each other. No intersections.
-I deleted the top face of the cylinder and the bottom square face because they aren’t needed and we don’t need intersections created where they pass through the other faces. Then select all geometry for the sides of both shapes, right click and choose Intersect Faces>With Selection.
-After the intersect operation has completed.
-After deleting the waste portion of the cylinder.
-After deleting the rest of the waste.